Electrical engineering

1. MICRO PROCESSOR ASSIGN.
PRESENTATION. - 2
Batch 5

2. OUR TOPIC IS:
TRAFFIC LIGHT
CONTROL
SYSTEM

3. We mean:

4. NEED FOR THE SYSTEM :
 Traffic lightsstoplights/ traffic lamps/
traffic signals/ signal lights/ robots/
semaphore
 signaling devices
 positioned at road intersections,
pedestrian crossings and other locations
 to control competing flows of traffic.
 Preventing accidents
 Improving safety
 Minimize travel time

5. ABOUT THE COLORS OF TRAFFIC LIGHT
CONTROL
 Traffic lights alternate the right of way of road
users by displaying lights of a standard color
(red, yellow/amber, and green)
 By using a universal color code (and a
precise sequence to enable comprehension
by those who are color blind

6. SIGNAL FOR VEHICLE

7. SIGNAL FOR PEDESTRIAN

8. PROCESSOR USED:
8085
Microprocessor

9. WHY 8085?
 Sufficient memory for the given scenario
 Basic units to be interfaced are supported by
8085
 Less complicated in the aspect of coding
 Supports the necessary instruction sets
 Simple and robust

10. 5v Power
Supply
8085
Microprocessor
7 Segment
Display
LED Display
TIMER
INPUT
DISPLAYS
WAITING
OUTPUT
SIGNAL
BASIC BLOCK DIAGRAM

11. BLOCK DIAGRAM:

12. ALGORITHM

16. STATE DIAGRAM FOR TRAFFIC CONTROLER

17. PROPOSED SYSTEM:

18. HARWARE DETAILS:
2 PARTS
• 8085 Processor
based system
• Traffic Light
Controller
Interface board

19. IC’S USED:
8085 Micro processor
8255 PPI
8253 Timer
8279 Keyboard and Display Interface

20. 8255 PIN

21. INTERFACING WITH 8085:

22. I/O MAP:

23. 8255 FOR TRAFFIC LIGHT :
 MVI A, 80H : Initialize 8255, port A and
port B
 OUT 83H (CR) : in output mode
 START:
 MVI A, 09H
 OUT 80H (PA) : Send data on PA to glow
R1 and R2
 MVI A, E4H
 OUT 81H (PB) : Send data on PB to glow
G3 ,G4,G3R,G4R
 MVI A, 0CH
 OUT 82H (PB) : Send data on PC to glow
G3 R ,G4L

24.  MVI C, 28H : Load multiplier count for
delay
 CALL DELAY : Call delay subroutine
 MVI A, 09H
 OUT 80H (PA) : Send data on PA to glow R1 and
R2
 MVI A, 24H
 OUT 81H (PB) : Send data on PB to glow G3 and
G4
 MVI A, 00H
 OUT 82H (PB) : Send data on PC to disable G3 L
,G4L & Enable Pedestrian Crossing
 MVI C, 28H : Load multiplier count for
delay

25.  MVI A, 12H
 OUT (81H) PA : Send data on Port A to glow Y1 and
Y2
 OUT (81H) PB : Send data on port B to glow
Y3 and Y4
 MVI C, 0AH : Load multiplier count for delay
 CALL DELAY : Call delay subroutine
 MVI A, E4H
 OUT (80H) PA : Send data on port A to glow G1 and
G2,G1R,G2R
 MVI A, 09H
 OUT (81H) PB : Send data on port B to glow
R3 and R4
 MVI C, 28H : Load multiplier count for delay
 MVI A, 03H
 OUT 82H (PB) : Send data on PC to glow G1
L ,G2L
 CALL DELAY : Call delay subroutine

26.  MVI A, E4H
 OUT (80H) PA : Send data on port A to glow G1 and G2
 MVI A, 09H
 OUT (81H) PB : Send data on port B to glow R3
and R4
 MVI A, 00H
 OUT 82H (PB) : Send data on PC to disable G1 L
,G2L  Enable Pedestrian
Crossing
 MVI C, 28H : Load multiplier count (40i?) for delay
 CALL DELAY : Call delay subroutine
 MVI A, 12H
 OUT PA : Send data on port A to glow Y1
and Y2
 OUT PB : Send data on port B to glow Y3
and Y4
 MVI C, 0AH : Load multiplier count (10i?) for delay

27. DELAY SUBROUTINE:
 DELAY:
 DCR C : Decrement counter
 JNZ DELAY
 RET : Return to main program

28. LOGIC FOR PEDESTRIANS CROSSING

29. 8279 DISPLAY INTERFACE

30. 7 SEGMENT DISPLAY FOR TRAFFIC
LIGHT- WORKING :
The processor initializes the look up table
pointer. The look up table contains the
format for the 7 segment display

31. SEGMENT CODES FOR COMMON CATHODE
DISPLAY

32. LOOK UP TABLE FOR DIGITS 1-8:

33.  The microprocessor sends the data to the
latch
 From the latch, the data is sent to 8279
Display Interface
 It then stores the data in its 16 X 8 Internal
RAM

34. WRITING TO RAM:
There are 6 seven segment displays in 8085 kit
I 4 displays address
II 2 displays data
Here we make use of last two displays to interpret
the waiting time in each signal

35.  Hence we require a decoder to select among the
two displays
 Since there are 6 displays, we require a 3X8
decoder(74138)
 The inputs to these pins will be s1,s2,s0 of 8279
 Output of decoder  xx0 Left display xx1 
Right Display
 Output to the seven segment displays will be from
A3-0 and B3-0

36. ANALOG TO DIGITAL CONVERTOR
 This is required because 8085 will require only
+5V power supply

37. REFERENCES:
 rbinnovations.com
 gobookee.net
 seminarprojects.com
 eprlabs.blogspot.com

38.  Batch members
DINESH .S (11I309)
MARIA JERIN .J (11I324)
SARATHY .K (11I340)
SRINIVASAN .R (11I347)
SUBASH .S (11I348)
MURALI KRISHNAN .P (12I469)

39. FINAL PRODUCT: